Semi-Natural Superabsorbents Based on Starch-g-poly(acrylic acid): Modification, Synthesis and Application

Abstract

Biopolymer-based superabsorbent polymers (SAPs) are being synthesized and investigated as a biodegradable alternative for an entirely synthetic SAPs, particularly those based on acrylic acid and its derivatives. This article focuses on the chemical modification of starch (S), and synthesis of new potentially biodegradable polymers using acrylic acid (AA) as side chain monomer and crosslinking mediator together with N,N’-methylenebisacrylamide (MBA). The graft co-polymerization was initiated by ceric ammonium nitrate (CAN) or potassium persulfate (KPS), leading to different reaction mechanisms. For each of the initiators, three different synthetic routes were applied. The structures of new bio-based SAPs were characterized by means of IR spectroscopy. Thermogravimetric measurements were made to test the thermal stability, and morphology of the samples were examined using scanning electron microscopy (SEM). Physico-chemical measurements were performed to characterize properties of new materials such as swelling characteristics. The water absorption capacity of resulting hydrogels was measured in distilled water and 0.9% NaCl solution.

An Efficient Approach to Prepare Water-Redispersible Starch Nanocrystals from Waxy Potato Starch

“…The absorption peaks near 995 cm −1 and 1150 cm −1 were caused by stretching vibrations of C–O [ 36 ]. The absorption peak at 1078 cm −1 was caused by stretching vibrations of O–C in the C–O–C group of the glucose ring [ 37 , 38 ]. According to the analysis of Ren et al, the absorption peak of P=O vibrations is relatively weak at 1400–1150 cm −1 [ 18 ].…”

Synthesis and Characterization Superabsorbent Polymers Made of Starch, Acrylic Acid, Acrylamide, Poly(Vinyl Alcohol), 2-Hydroxyethyl Methacrylate, 2-Acrylamido-2-methylpropane Sulfonic Acid

“…Initial swelling rate is determined from the formula derived from Voigt viscoelasticity model combining a spring with dashpot. The equation allows us to manage a fast transition from a high initial rate toward a very slow rate near the end of the process [12]. Using this approach, one comes to following equation:…”

“…There has been a lot of research on the chemical modification and cross-linking of cellulose. However, starch modification was also tested with various synthetic monomers, e.g., acrylic acid [ 9 , 10 , 11 , 12 , 13 , 14 , 15 ], acrylamide [ 16 , 17 , 18 ], methacrylamide [ 19 , 20 ], acrylonitrile [ 21 ], vinyl alcohol [ 22 ], 2-acrylamido-2-methylpropanesulfonic acid [ 23 , 24 ], styrene [ 25 ], vinylimidazole [ 26 ].…”

The Influence of Monomer Composition and Surface-CrossLinking Condition on Biodegradation and Gel Strength of Super Absorbent Polymer

“…However, they have disadvantages such as being toxic to the skin and are environmentally unfriendly [ 9 , 10 ]. Accordingly, many researchers have studied the synthesis of SAPs using bio-based monomers to reduce the content of petroleum-based monomers such as AA and acrylamide [ 11 , 12 , 13 , 14 , 15 , 16 ]. Typically, potato starch, cassava starch, corn starch, and cellulose have been widely used in biomass-based SAP synthesis because these are inexpensive and widely available.…”